<p>Background: Confirmation of consciousness disturbance at the injury and identification of morphological brain damage are essential to authorize the neuro­psychological impairments by traffic accident in the process of compensation for damages. However, com­pensation for damages is sometimes claimed in the cases whose consciousness disturbance is not evident and organic brain damage is not identified in the brain images. In the present study, we analyzed trial cases in which the neuropsychological impair­ments by traffic accident was contended at court, and clarified important factors in the judgment of the com­pen­sation litigation for damages.</p><p>Methods: Using precedent search system "Westlaw^Ⓡ Japan" with keywords of "neuropsychological impairments" and "impediment", we extracted trial cases in which approval or non–approval of neuropsycho­logical impairments by traffic accident was judged at court from January, 2013 until December, 2017. We analyzed the reasons for the judgment especially in terms of consciousness disturbance at the injury, morpho­logical brain damage at acute stage and radio­logical findings including advanced MR images and radioisotope examinations. We further analyzed the cases claimed that mild traumatic brain injury (mTBI) causes the neuropsycho­logical impairments.</p><p>Results: During this period, 67 trial cases were extracted from the precedent search system. Sixteen cases were judged suffering from the neuropsychological impairments by traffic accident and 51 cases were denied. In 16 approved cases, 10 cases were approved as the neuropsychological impairments due to organic brain dam­age and 6 cases were considered as non–organic mental disorders by traffic accident. mTBI was claimed in 25 cases, but none of them were approved as the neuro­psychological impairments. The role of recently developed brain studies including advanced MR images and radio­isotope examinations was not justified in the judgment of organic neuropsychological impairments by traffic accident.</p><p>Conclusion: Several important points for neurosurgeons who diagnose and manage the patients with traumatic neuropsycho­logical impairments by traffic accident have clarified in this study. Future registration and prospective studies are necessary to further support the patients with the neuropsychological impairments after head trauma including mTBI by traffic accident.</p>